Transcript for Colorado's Deadliest Avalanche in 50 Years Kills Five Snowboarders

It happened in a flash. A deadly avalanche in the colorado rocky mountains. A group of snowboarders were buried alive. Five of them died. Only one survivor. The thrill seekers, the back country slopes are irresistible. But this year, they are dangerous. And clayton sandell explains. Reporter: It is colorado's worst avalanche disaster in 60 years. On saturday, six snowboarders went to love larnd see area. They triggered a an avalanche, two football fields wide and four football fields long. It's going to be a mass casualty situation. Reporter: Five snowboarders were killed. Buried under at least eight feet of snow. ALL WERE IN THEIR 30s, INCLUDING Rick, an experienced avalanche expert and a member of an organization dedicated to avalanche safety. Only one man made it out unhurt. This latest deadly incident the brings the number of people killed by avalanche this season to 24. Forecasters warned of a dangerous potential for avalanche on saturday. But the men had the right safety ge gear and kneake the right decisions. But none of that mattered when the mountain gave way. Clayton sandell, abc news, denver.

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